Mitral stenosis: symptoms and auscultatory findings
THE CONTEXT
Mitral stenosis commonly causes progressive limitation of exercise and characteristic heart sounds; physical signs may appear before symptoms.
Symptoms and complications
•
Effort-related breathlessness is usually the dominant symptom. Exercise tolerance often declines gradually over years, and patients may underestimate their disability until treatment.
•
Acute pulmonary oedema or pulmonary hypertension can cause haemoptysis. Low cardiac output commonly causes fatigue.
•
Thromboembolism is a common complication, particularly with atrial fibrillation and dilated atria. Before anticoagulant therapy, emboli accounted for one-quarter of deaths.
Heart sounds and severity
•
Physical signs often precede symptoms, making their recognition particularly important in pregnancy.
•
Rising left atrial pressure increases the forces opening and closing the mitral valve. The first heart sound becomes loud and may be palpable as a tapping apex beat.
•
An opening snap may be audible. It moves closer to the second heart sound as stenosis becomes more severe and left atrial pressure increases.
•
A heavily calcified valve may produce neither an audible first heart sound nor an opening snap.
Murmur and imaging
•
Turbulent flow produces a low-pitched mid-diastolic murmur and sometimes a thrill.
•
Exercise accentuates the murmur. In sinus rhythm, atrial systole produces pre-systolic accentuation; early disease may present with only a pre-systolic murmur.
•
Echocardiography can show reduced mitral valve opening in diastole, while colour Doppler demonstrates turbulent flow.
•
A pressure gradient exists between the left atrium and left ventricle during diastole.